And as far as I understand, the training code is where the secret sauce lies.
And as far as I understand, the training code is where the secret sauce lies.
Secret sauce is in the ML compiler and accelerator used, but all those improvements simply lower the cost of training a model. You could still do it on a regular GPU, it would just take you more time.
In the case of Google, they probably used TPU chips that you can't get direct 'bare metal' access to anyway, so none of that code would have helped.
The actual optimizer used and parameters (like the learning rate schedule) is normally published in the research paper.
1600 inferences per move * 1ms per inference * 250 moves/game * 30M games played = 12B seconds. 140k days; muzero with gumbel brought down the 1600 to ~40, but either way, you need some more scale.
It turns out a lot of the difficulties, judgment calls, and implementation details involve data pipelining. Some of those choices affect the final skill ceiling you reach. Which ones? How much? Are they path dependent? Well, you'll need to run it more than once...